Cellular wireless communications systems, for example, are designed to serve multiple wireless-enabled devices distributed over a large geographic area by dividing the area into regions called “cells”. At or near the center of each cell, a network-side access device (e.g., an access point) is located to serve client devices located in the cell and commonly referred to as “access terminals.” Examples of access terminals include cellular telephones, laptops, PDAs, and other wireless-enabled devices. An access terminal generally establishes a call, also referred to as a “communication session,” with an access point to communicate with other entities (e.g., servers) in the network.